Lenze DDS v2.3 - Manual (Page 304)

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IEC 61131-3 Standard functions
14-12
l
DDS EN 2.3
14.5 Edge detection
14.5.1 R_TRIG
Rising edge detector
FUNCTION_BLOCK R_TRIG
VAR_INPUT
CLK : BOOL;
END_VAR
VAR_OUTPUT
Q : BOOL;
END_VAR
VAR
M : BOOL := FALSE;
END_VAR
Q := CLK AND NOT M;
M := CLK1;
END_FUNCTION_BLOCK
As long as the input variable CLK is FALSE,
the output Q and the auxiliary variable M will be FALSE .
As soon as CLK returns TRUE,
Q will first return TRUE
and then M will be switched to TRUE .
I.e.: with every subsequent function call, Q will return FALSE until CLK has a falling and another rising
edge.
Examples
Declaration:
RTRIGInst : R_TRIG;
IL FBD
CAL RTRIGInst(CLK:=VarBOOL1)
LD RTRIGInst.Q
ST VarBOOL2
ST
RTRIGInst(CLK:=VarBOOL1);
VarBOOL2:=RTRIGInst.Q;
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